Article first published online: 3 JUN 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Volume 200, Issue 1, pages 158–171, October 2013
How to Cite
Hoser, R., Żurczak, M., Lichocka, M., Zuzga, S., Dadlez, M., Samuel, M. A., Ellis, B. E., Stuttmann, J., Parker, J. E., Hennig, J. and Krzymowska, M. (2013), Nucleocytoplasmic partitioning of tobacco N receptor is modulated by SGT1. New Phytologist, 200: 158–171. doi: 10.1111/nph.12347
- Issue published online: 26 AUG 2013
- Article first published online: 3 JUN 2013
- Manuscript Accepted: 29 APR 2013
- Manuscript Received: 27 MAR 2013
- Ministry of Science and Higher Education Republic of Poland. Grant Numbers: N302 015 31/1618, NN301 163235, N N301 318039
- disease resistance;
- MAPK ;
- nucleocytoplasmic shuttling;
- protein phosphorylation;
- tobacco (Nicotiana tabacum)
- SGT1 (Suppressor of G2 allele of SKP1) is required to maintain plant disease Resistance (R) proteins with Nucleotide-Binding (NB) and Leucine-Rich Repeat (LRR) domains in an inactive but signaling-competent state. SGT1 is an integral component of a multi-protein network that includes RACK1, Rac1, RAR1, Rboh, HSP90 and HSP70, and in rice the Mitogen-Activated Protein Kinase (MAPK), OsMAPK6. Tobacco (Nicotiana tabacum) N protein, which belongs to the Toll-Interleukin Receptor (TIR)-NB-LRR class of R proteins, confers resistance to Tobacco Mosaic Virus (TMV).
- Following transient expression in planta, we analyzed the functional relationship between SGT1, SIPK – a tobacco MAPK6 ortholog – and N, using mass spectrometry, confocal microscopy and pathogen assays.
- Here, we show that tobacco SGT1 undergoes specific phosphorylation in a canonical MAPK target-motif by SIPK. Mutation of this motif to mimic SIPK phosphorylation leads to an increased proportion of cells displaying SGT1 nuclear accumulation and impairs N-mediated resistance to TMV, as does phospho-null substitution at the same residue. Forced nuclear localization of SGT1 causes N to be confined to nuclei.
- Our data suggest that one mode of regulating nucleocytoplasmic partitioning of R proteins is by maintaining appropriate levels of SGT1 phosphorylation catalyzed by plant MAPK.